Triterpenoids are biosynthesized in plants by the cyclization of squalene. Although candidates for medicinal use, these naturally occurring molecules display relatively weak biological activity. Accordingly, chemists have sought to synthesize analogues of enhanced potency (Honda et al., 1997 & 1998).
Several synthetic analogs are reported to suppress the de novo formation of iNOS and COX-2 in macrophages that have been stimulated by IFN-γ or LPS (Suh et al., 1998; Honda et al., 2002). Another synthetic triterpenoid, 2-cyano-3,12-dioxoleana-1,9(11)-dien-28-oate (CDDO), exhibits anti-inflammatory and anti-proliferative activity (Honda et al., 1998 & 2000).
Studying the methyl ester of CDDO, which is methyl 2-cyano-3,12-dioxoleana-1,9(11)-dien-28-oate (CDDO methyl ester), Bore et al. (2002) determined a crystal structure. In that form, which is hydrated, water coordinates interactions that engender a particular crystal packing and structure.